The invention relates to an apparatus for feeding blasting material via a feed line into the central portion of the centrifugal wheel of a blasting unit, whereby in the central portion there is provided a distribution sleeve having a distribution opening, and in the distribution sleeve, together with the centrifugal wheel, an impeller having discharge openings rotates, with the blasting material that is to be accelerated entering the impeller in the axial direction.
With units that are equipped with centrifugal wheels, known, for example, from DE-OS 25 38 228, surfaces of metallic rolled products are freed of scale and/or rust before the surface receives a protective coating, with this being accomplished by flinging or throwing against the surface a blasting material comprised of fine metal particles. In such a centrifugal wheel, not all of the particles of the blasting material move radially and as parallel as possible to the blades as they are discharged outwardly out of the impeller. A significant number of these particles strike against the side panels and the blades, and rebound back from them in a manner similar to a ping pong ball, which not only has a negative effect upon the discharge velocity of the blasting material out of the centrifugal wheel, but also leads to a non-uniform distribution of the blasting material upon the surface that is to be cleaned. Due to the striking of the particles of blasting material against components of the centrifugal wheel, the latter are additionally subject to significant wear.
It is therefore an object of the invention to reduce the wear of the centrifugal wheel caused by the blasting material, and at the same time to produce a blasting pattern having a more uniform coverage over the entire discharge angle of the blasting material out of the centrifugal wheel having nearly parallel side walls.